PHASED ARRAY ANTENNA SYSTEM WITH ELECTRICAL TILT CONTROL

• US 20090322610A1
• Filed: 11/07/2007
• Published: 12/31/2009
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: Quintel Cayman Limited
• Original Assignee: Louis David Thomas, Philip Edward Hants
• Inventors: Thomas, Louis David, Hants, Philip Edward
• Granted Patent: US 9,252,485 B2
• Time in Patent Office: Days
• US Class Current: 342/372
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/0006 Particular feeding systems
• CPC Class Codes: H01Q 21/22 Antenna units of the array energised non-uniformly in amplitude or phase, e.g. tapered array or binomial array
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/2694 using also variable phase-shifters H01Q3/2688 takes precedence
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

A phased array antenna system with electrical tilt control incorporates a tilt controller (62) for splitting an input signal into three intermediate signals, two of which are delayed by variable delays T1 and T2 relative to the third. A corporate feed (64) contains splitters S3 to S10 and hybrids H1 to H6 for processing the intermediate signals to produce drive signals for elements of an antenna array (66); the drive signals are fractions and vector combinations of the intermediate signals. The tilt controller (62) and the corporate feed (64) in combination impose relative phasing on the drive signals as appropriate for phased array beam steering in response to variable delay of two intermediate signals relative to the third intermediate signal.

Claims

1. A phased array antenna system with electrical tilt control operative as a transmitter in transmit mode and incorporating:

a) an array of antenna elements;

b) tilt control means for splitting an input signal into at least first, second and third intermediate signals such that the at least first and second intermediate signals are each variably delayable relative to the third intermediate signal;

c) corporate feed means for processing the intermediate signals to produce drive signals for antenna elements, the drive signals at least partly comprising vector combinations of the intermediate signals; and

d) relative phasing for the drive signals imposed in combination by the tilt control means and the corporate feed means as appropriate for phased array beam steering in response to variable delay of the at least first and second intermediate signals relative to the third intermediate signal.

3. A phased array antenna system according to claim 1 wherein the tilt control means includes a respective variable delaying means for variably delaying each of the at least first and second intermediate signals relative to the third intermediate signal, the variable delaying means being arranged to provide delays which vary at like rates and one delay increasing while another reduces.

4. A phased array antenna system according to claim 3 wherein the variable delaying means are arranged to apply respective delays which are equal to one another in magnitude.

5. A phased array antenna system according to claim 1, wherein the corporate feed means is arranged to combine signals in neighbouring locations to avoid circuit cross-overs.

6. A phased array antenna system according to claim 1 wherein the corporate feed means is arranged to combine intermediate signals in neighbouring locations to produce drive signals for antenna elements and avoid circuit cross-overs.

7. A phased array antenna system according to claim 1 wherein the tilt control means and the corporate feed means are arranged to provide drive signals for antenna elements with a substantially linear phase front across the array.

8. A phased array antenna system according to claim 1 wherein the tilt control means and the corporate feed means are arranged to provide drive signals for antenna elements with an amplitude taper which suppresses side lobes and a substantially linear phase taper which tilts the beam of the array without compromising beam shape.

9. A phased array antenna system according to claim 1 wherein the tilt control means is a first tilt control means, and the system includes at least one other tilt control means and filtering means to isolate transmit and/or receive signals of different frequencies and provide a respective independent angle of electrical tilt associated with each tilt control means.

10. A phased array antenna system according to claim 1 wherein the tilt control means and the corporate feed means include splitting means implementing an amplitude taper such as a cosine, cosec or Dolph-Chebyshev amplitude taper.

11. A phased array antenna system according to claim 1 wherein the tilt control means includes only two variable delaying means for variably delaying only first and second intermediate signals relative to the third intermediate signal.

12. A phased array antenna system according to claim 1 wherein the tilt control means includes only four variable delaying means for variably delaying only first, second, fourth and fifth intermediate signals relative to the third intermediate signal.

13. A phased array antenna system according to claim 1 wherein the array of antenna elements has seven, eleven, fifteen or nineteen antenna elements.

14. A phased array antenna system according to claim 1 wherein the tilt control means and the corporate feed means include splitting means and hybrid combining means for splitting and combining signals and implemented as double box quadrature hybrids and sum and difference hybrids.

15. A phased array antenna system according to claim 1 wherein some of the drive signals are fractions of individual intermediate signals and other drive signals are vector sums or differences of fractions of two intermediate signals.

2. A phased array antenna system with electrical tilt control operative as a receiver in receive mode and incorporating:

a) an array of antenna elements;

b) corporate feed means for processing received signals from antenna elements to produce at least first, second and third intermediate signals at least partly comprising vector combinations of the received signals;

c) tilt control means for converting the intermediate signals into an output signal by variably delaying the at least first and second intermediate signals relative to the third intermediate signal and combining the delayed intermediate signals with the third intermediate signal to provide the output signal; and

d) relative phasing for the intermediate signals imposed in combination by the corporate feed means and the tilt control means as appropriate for phased array beam steering in response to variable delay of the at least first and second intermediate signals relative to the third intermediate signal.

16. A method of operating a phased array antenna system with electrical tilt control as a transmitter in transmit mode, the antenna system incorporating an antenna with an array of antenna elements and the method having the steps of:

a) splitting an input signal into at least first, second and third intermediate signals,

b) variably delaying the at least first and second intermediate signals relative to the third intermediate signal;

c) processing the intermediate signals to produce drive signals for antenna elements, the drive signals at least partly comprising vector combinations of the intermediate signals; and

d) relatively phasing the drive signals as appropriate for phased array beam steering in response to variable delay of the at least first and second intermediate signals relative to the third intermediate signal.

18. A method of operating a phased array antenna system according to claim 16 including the step of variably delaying each of the at least first and second intermediate signals relative to the third intermediate signal with delays which vary at like rates, and one delay increasing while another reduces.

19. A method of operating a phased array antenna system according to claim 18 wherein the step of variably delaying applies respective delays which are equal to one another in magnitude.

20. A method of operating a phased array antenna system according to claim 16 including combining signals in neighbouring locations to avoid circuit cross-overs.

21. A method of operating a phased array antenna system according to claim 16 including combining intermediate signals in neighbouring locations to produce drive signals for antenna elements and avoid circuit cross-overs.

22. A method of operating a phased array antenna system according to claim 16 including providing drive signals for antenna elements with a substantially linear phase front across the array.

23. A method of operating a phased array antenna system according to claim 16 including providing drive signals for antenna elements with an amplitude taper which suppresses side lobes and a substantially linear phase taper which tilts the beam of the array without compromising beam shape.

24. A method of operating a phased array antenna system according to claim 16 including isolating transmit and/or receive signals of different frequencies and provide independent angles of electrical tilt associated with different tilt controls.

25. A method of operating a phased array antenna system according to claim 16 including signal splitting to implement an amplitude taper such as a cosine, cosec or Dolph-Chebyshev amplitude taper.

26. A method of operating a phased array antenna system according to claim 16 including variably delaying only first and second intermediate signals relative to the third intermediate signal.

27. A method of operating a phased array antenna system according to claim 16 including variably delaying only first, second, fourth and fifth intermediate signals relative to the third intermediate signal.

28. A method of operating a phased array antenna system according to claim 16 wherein the array of antenna elements has seven, eleven, fifteen or nineteen antenna elements.

29. A method of operating a phased array antenna system according to claim 16 including splitting and combining signals by means of double box quadrature hybrids and sum and difference hybrids.

30. A method of operating a phased array antenna system according to claim 16 wherein some of the drive signals are fractions of individual intermediate signals and other drive signals are vector sums or differences of fractions of two intermediate signals.

17. A method of operating a phased array antenna system with electrical tilt control as a receiver in receive mode, the antenna system incorporating an antenna with an array of antenna elements and the method having the steps of:

a) processing received signals from antenna elements to produce at least first, second and third intermediate signals at least partly comprising vector combinations of the received signals;

b) converting the intermediate signals into an output signal by variably delaying the at least first and second intermediate signals relative to the third intermediate signal and combining the delayed intermediate signals with the third intermediate signal to provide the output signal; and

c) relatively phasing the intermediate signals for phased array beam steering in response to variable delay of the at least first and second intermediate signals relative to the third intermediate signal.